Yesterday I posted a msg about my non-working KRX3 subRX, and the PL2 and VCO Md error messages I was getting. On advice from Wayne, I did the ADC ref calbration, measuring the ref voltage at the ACC connector as 4.973V. After setting the ref voltage to that value and redoing the VCO MD calibration, the subreceiver worked perfectly. Jim W8ZR